Board Foot Calculator
Calculate lumber volume in board feet and estimate costs for construction and woodworking projects
Calculate Board Feet
Choose calculation method based on your material type
How many lumber pieces you need
Length of the lumber piece
Width of the lumber piece
Thickness of the lumber piece
Enter lumber price to calculate total cost and cost per linear foot
Board Foot Results
Formula: Board Feet = Length (ft) × Width (in) × Thickness (in) ÷ 12
Calculation: 0.000 ft × 0.000" × 0.000" ÷ 12 = 0.000 BF per piece
Total: 0.000 BF × 1 pieces = 0.000 BF
Key conversions: 1 BF = 144 cubic inches = 1/12 cubic foot
Lumber Size Analysis
Example Calculations
Hardwood Deck Example
Project: Hardwood decking boards
Pieces needed: 25 boards
Dimensions: 8 feet × 5.5 inches × 1.5 inches
Price: $6.50 per board foot
Calculation
Board feet per piece = 8 ft × 5.5 in × 1.5 in ÷ 12
Board feet per piece = 66 ÷ 12 = 5.5 BF
Total board feet = 5.5 BF × 25 pieces = 137.5 BF
Total cost = 137.5 BF × $6.50 = $893.75
Cost per linear foot = $6.50 × 5.5 × 1.5 ÷ 12 = $4.48/ft
Log Scaling Example
Project: Oak logs for milling
Number of logs: 3
Diameter: 16 inches (small end, no bark)
Length: 12 feet each
Price: $3.25 per board foot
Doyle Rule Calculation
BF per log = ((16 - 4) ÷ 4)² × 12
BF per log = (12 ÷ 4)² × 12 = 3² × 12 = 108 BF
Total board feet = 108 BF × 3 logs = 324 BF
Total value = 324 BF × $3.25 = $1,053
Bulk Volume Conversion
Scenario: Lumber pile measurement
Total volume: 85 cubic feet
Price: $4.75 per board foot
Conversion
Board feet = 85 cubic feet × 12 BF/cubic foot
Board feet = 1,020 BF
Total value = 1,020 BF × $4.75 = $4,845
Common Lumber Sizes (Board Feet per Linear Foot)
2×4 Board Feet by Length
Unit Conversions
- • 144 cubic inches
- • 1/12 cubic foot (0.0833 cu ft)
- • 2,359.7 cubic cm
- • 0.002359 cubic meters
- • 2.36 liters
One board foot is the volume of a board that is 1 foot long, 1 foot wide, and 1 inch thick.
Doyle Rule is conservative but widely used. International 1/4" rule gives higher yields.
Wood Density (lbs per BF)
Lumber Tips
Always measure actual dimensions, not nominal sizes
Add 10-15% extra for waste and cuts
Consider lumber grade for your project needs
Check moisture content for indoor projects
Compare prices per board foot, not per piece
Understanding Board Feet Calculations
What is a Board Foot?
A board foot is a unit of measurement for lumber volume. Unlike square footage which measures area, board footage measures volume. One board foot equals the volume of a board that is 1 foot long, 1 foot wide, and 1 inch thick (144 cubic inches).
Standard Formula
Board Feet = Length (ft) × Width (in) × Thickness (in) ÷ 12
Why Use Board Feet?
- •Standard measurement for pricing lumber
- •Allows comparison of different sized boards
- •Helps estimate material costs accurately
- •Industry standard for hardwood lumber
Calculation Methods
Standard Lumber
For dimensional lumber and boards. Uses length in feet, width and thickness in inches.
Log Scaling (Doyle Rule)
For estimating board feet in logs: ((Diameter - 4) ÷ 4)² × Length. Conservative estimate commonly used in North America.
Bulk Volume
Convert known cubic footage to board feet. Useful for lumber piles or bulk measurements.
Important: Actual lumber dimensions differ from nominal sizes. A "2×4" is actually 1.5" × 3.5". Always use actual dimensions for accurate calculations.
Board Foot Applications
Construction Lumber
- • Framing materials
- • Structural beams
- • Dimensional lumber
- • Cost comparison
Hardwood & Woodworking
- • Furniture projects
- • Cabinet making
- • Flooring materials
- • Specialty wood purchases
Forestry & Logging
- • Log scaling
- • Timber sales
- • Forest inventory
- • Mill planning
Measurement Best Practices
Accuracy Tips
- ✓Always use actual dimensions, not nominal sizes
- ✓Measure to the nearest 1/8 inch for precision
- ✓Account for variations in lumber dimensions
- ✓Consider waste factor (typically 10-15%)
Cost Planning
- ✓Compare prices per board foot, not per piece
- ✓Factor in delivery costs for bulk orders
- ✓Consider lumber grade for project requirements
- ✓Check moisture content for indoor projects
Complete Guide to Buying Lumber: How to Calculate and Save Money
Step-by-Step Lumber Purchasing Process
1. Determine Your Project Requirements
Before purchasing lumber, create a detailed cut list including:
- Dimensions: Length, width, and thickness for each piece
- Quantity: Number of pieces needed
- Species: Type of wood (pine, oak, cedar, etc.)
- Grade: Quality level needed (select, #1, #2, utility)
- Moisture Content: Kiln-dried for indoor, green for outdoor
2. Calculate Board Feet Needed
Use our calculator to determine total board feet. Add 10-15% for waste, defects, and mistakes. For complex projects with many cuts, consider adding 20% extra material. This waste factor accounts for unusable end pieces, knots, warping, and cutting errors.
3. Compare Pricing Options
Lumber is typically priced by board foot for hardwoods and by piece for construction lumber:
- Always convert piece pricing to cost per board foot for comparison
- Consider bulk discounts for large orders (100+ board feet)
- Compare local lumberyards vs. big box stores vs. specialty suppliers
- Factor in delivery costs for heavy or long pieces
4. Inspect Before Purchasing
When selecting lumber at the yard:
- Check for warping, cupping, and bowing along the length
- Look for large knots, splits, or cracks
- Verify actual dimensions match labeled sizes
- Inspect end grain for checking (small cracks)
- Choose straight pieces with minimal defects
Understanding Lumber Grades and Quality Standards
🪵 Softwood Lumber Grades
SELECT GRADE
- B & Better (Supreme): Highest quality, virtually defect-free
- C Select: Few minor defects, excellent for finishing
- D Select: Some defects but still high quality
- Best for: Fine woodworking, furniture, interior trim
COMMON GRADE
- #1 Common: Tight knots, minor defects allowed
- #2 Common: Larger knots and defects present
- #3 Common: Considerable defects, economy grade
- Best for: Framing, general construction, shelving
🌳 Hardwood Lumber Grades
NHLA GRADES (National Hardwood Lumber Association)
- FAS (Firsts and Seconds): 83.3% clear face, best grade
- FAS 1-Face: One face FAS quality, other side #1 Common
- #1 Common: 66.7% clear, good for most projects
- #2 Common: 50% clear, economy hardwood
GRADE SELECTION GUIDE
- Furniture/Cabinets: FAS or FAS 1-Face
- Flooring: #1 Common minimum
- Craft Projects: #2 Common acceptable
- Hidden Parts: Any grade sufficient
📏 Dimensional Lumber Standards
NOMINAL vs. ACTUAL SIZES
- 2×4 actual: 1.5" × 3.5" (not 2" × 4")
- 2×6 actual: 1.5" × 5.5"
- 2×8 actual: 1.5" × 7.25"
- 1×6 actual: 0.75" × 5.5"
- Always use actual dimensions for calculations!
PRESSURE-TREATED LUMBER
- Ground Contact: 0.40 retention level
- Above Ground: 0.25 retention level
- Marine Grade: 0.60+ retention level
- Allow to dry before painting or staining
💧 Moisture Content Standards
MOISTURE CATEGORIES
- S-GRN (Green): Over 19% MC, not dried
- S-DRY: 19% MC or less
- KD (Kiln-Dried): 12-15% MC
- KD-HT: Kiln-dried and heat-treated
PROJECT GUIDELINES
- Interior furniture: 6-8% MC ideal
- Interior trim: 8-10% MC
- Flooring: Match ambient humidity (6-9%)
- Outdoor projects: 12-15% MC acceptable
Troubleshooting Common Lumber Problems
❌ Warping & Bowing
Causes:
- Uneven moisture content in wood
- Improper storage (standing on end)
- Poor drying techniques
- Wood stored in humid environments
Prevention & Solutions:
- Store lumber flat with support every 16-24"
- Use kiln-dried lumber for indoor projects
- Acclimate wood to project location for 1-2 weeks
- Seal end grain immediately after cutting
- Rip warped boards into narrower pieces
⚠️ Splitting & Checking
Causes:
- Too-rapid drying of wood
- Large temperature fluctuations
- Nails or screws too close to ends
- Seasonal wood movement
Prevention & Solutions:
- Pre-drill holes within 2" of board ends
- Use end grain sealer on cut ends
- Maintain consistent humidity levels
- Allow proper wood acclimation time
- Use construction adhesive with fasteners
⚠️ Cupping & Twisting
Causes:
- Moisture absorbed on one face only
- Improper stacking during storage
- Wood cut too close to tree's pith
- Unequal exposure to moisture
Prevention & Solutions:
- Stack with stickers between layers
- Finish all sides of boards equally
- Install bark side up for decking
- Use edge grain boards when possible
- Mill twisted boards into smaller pieces
📊 Incorrect Board Feet Calculation
Common Mistakes:
- Using nominal instead of actual dimensions
- Mixing up unit conversions
- Not accounting for waste factor
- Forgetting to multiply by quantity
How to Avoid:
- Always measure actual dimensions
- Use our calculator for accuracy
- Add 10-15% waste factor
- Double-check all calculations
- Create detailed cut lists before purchasing
Best Practices for Lumber Selection and Storage
✅ DO
- ✓
Measure Actual Dimensions
Always use actual lumber dimensions, not nominal sizes
- ✓
Add Waste Factor
Include 10-15% extra for mistakes and defects
- ✓
Inspect Before Buying
Check for warping, knots, and defects
- ✓
Store Properly
Keep lumber flat, dry, and well-supported
- ✓
Acclimate Wood
Let lumber adjust to project location humidity
❌ DON'T
- ✗
Store Lumber Vertically
Vertical storage causes warping and bowing
- ✗
Buy Without Measuring
Always calculate exact quantities needed
- ✗
Mix Moisture Content
Don't combine green and kiln-dried lumber
- ✗
Ignore Wood Movement
Account for expansion/contraction in designs
- ✗
Store in Damp Areas
Moisture causes mold, rot, and warping
💡 PRO TIPS
- •
Buy Longer Lengths
Longer boards often have fewer defects per foot
- •
Compare Board Foot Pricing
Convert all prices to cost per BF for comparison
- •
Use Stickers for Storage
Space boards 1" apart with stickers for air flow
- •
Check End Grain
Vertical grain is more stable than flat grain
- •
Buy Local When Possible
Wood adapted to local climate performs better
Frequently Asked Questions About Board Feet
What's the difference between board feet and linear feet?
Board feet measure volume (length × width × thickness), accounting for all three dimensions of lumber. Linear feet only measure length, ignoring width and thickness. For example, a 2×4 and a 2×12 that are both 8 feet long have the same linear footage (8 feet), but very different board footage (5.33 BF vs 16 BF). Board feet is used for pricing because it reflects the actual amount of wood, while linear feet is used for measuring distance or spans.
Why do actual lumber dimensions differ from nominal sizes?
Lumber is initially cut to nominal dimensions (2"×4", 2"×6", etc.) when green (wet). During the drying and planing process, wood shrinks and material is removed to create smooth surfaces. A "2×4" becomes 1.5"×3.5" after drying and surfacing. This standardization ensures consistent dimensions across different mills and suppliers. Always use actual dimensions when calculating board feet or planning projects. The nominal names are traditional lumber industry terminology that persists even though the physical dimensions are smaller.
How much waste factor should I add to my lumber order?
Waste factors vary by project complexity and lumber quality:
- 10% waste: Simple projects with straight cuts, high-grade lumber
- 15% waste: Average projects with some complex cuts, standard lumber
- 20% waste: Complex projects with many angled cuts, lower-grade lumber
- 25% waste: Intricate patterns, rustic lumber with many defects
Also consider that longer boards (12+ feet) tend to have more defects per foot than shorter boards. First-time builders should add extra waste factor for mistakes and learning curve.
Can I calculate board feet for round logs?
Yes! Our calculator includes log scaling using the Doyle Rule. Measure the diameter at the small end (inside the bark) and the log length. The Doyle formula is: ((Diameter - 4) ÷ 4)² × Length. Note that this is a conservative estimate - actual yield depends on sawing method and log quality. Other scaling rules (Scribner, International 1/4") may give different results. The Doyle Rule underestimates small logs and is most accurate for logs 28+ inches in diameter. For more accurate yield predictions, consult with a sawmill operator.
What's the best way to store lumber to prevent warping?
Follow these storage best practices:
- Store horizontally: Never lean boards vertically against walls
- Use support: Place supports every 16-24 inches to prevent sagging
- Add stickers: Use 1" thick spacers between layers for air circulation
- Keep level: Ensure storage surface and stack are perfectly level
- Control environment: Store in dry area with consistent temperature
- Cover but ventilate: Protect from rain but allow air flow
- Weight the top: Add weight evenly across top layer to prevent cupping
How do I choose between different wood species for my project?
Consider these factors when selecting wood species:
- Hardness: Oak/maple for floors, pine for walls/ceilings
- Rot resistance: Cedar/redwood for outdoor, any for indoor
- Appearance: Cherry/walnut for fine furniture, pine for painted projects
- Workability: Pine/poplar easy to cut, oak/maple more challenging
- Cost: Pine/fir economical, hardwoods more expensive
- Availability: Use locally common species when possible
- Stability: Quartersawn lumber more stable than plainsawn
What moisture content should I look for in lumber?
Target moisture content depends on the project location and use. For interior projects, aim for 6-8% MC to match typical indoor humidity levels. Exterior projects can use 12-15% MC lumber. Wood will continue to adjust to ambient humidity, so it's crucial to acclimate lumber in the project location for 1-2 weeks before installation. Use a moisture meter (under $30) to check MC before purchasing. Green lumber (over 19% MC) is cheaper but will shrink significantly as it dries, potentially causing gaps and warping in your project.
Is it cheaper to buy lumber by the board foot or by the piece?
It depends on the lumber type and source. Construction lumber (2×4s, 2×6s) is typically sold by the piece at big box stores, while hardwood lumber is sold by board foot at specialty lumber yards. To compare prices, always convert to cost per board foot. Sometimes buying longer lengths and cutting them yourself is cheaper than buying multiple short pieces. Bulk purchases (100+ BF) often qualify for discounts. For small projects, piece pricing may be more convenient. For large projects or hardwood purchases, board foot pricing typically offers better value and flexibility.
How do I calculate the weight of my lumber order?
Weight varies by wood species and moisture content. Use these approximate weights per board foot:
- Cedar: 2.2 lbs/BF (lightweight, good for decks)
- Pine: 2.5 lbs/BF (common softwood)
- Douglas Fir: 2.7 lbs/BF (structural lumber)
- Mahogany: 3.5 lbs/BF (stable hardwood)
- Maple: 3.75 lbs/BF (flooring favorite)
- Oak: 3.875 lbs/BF (classic hardwood)
- Walnut: 4.0 lbs/BF (premium hardwood)
Our calculator provides weight estimates for common species. For delivery planning, add 10-20% to account for moisture and pallets/packaging.
What's the difference between construction grade and finish grade lumber?
Construction grade (Stud, #2, #3) is designed for structural applications where appearance doesn't matter. It may have knots, wane (missing edges), and rough spots, but meets strength requirements for framing, joists, and blocking. Finish grade (Select, Clear, FAS) has minimal defects, consistent grain, and smooth surfaces suitable for visible applications like trim, cabinetry, and furniture. Construction grade is significantly cheaper but requires more sorting for usable pieces. For projects with both hidden and visible components, buy construction grade for framing and finish grade for surfaces. Never use construction grade lumber for fine woodworking or anywhere appearance matters.
Wood Species Selection Guide
Common Softwoods
Pine (2.5 lbs/BF)
Best for: Interior trim, painted projects, furniture
Pros: Easy to work, affordable, readily available
Cons: Soft, dents easily, knots can be problematic
Douglas Fir (2.7 lbs/BF)
Best for: Structural framing, beams, outdoor projects
Pros: Strong, stable, attractive grain
Cons: Can be splintery, moderate price
Cedar (2.2 lbs/BF)
Best for: Outdoor furniture, decks, siding, closets
Pros: Naturally rot-resistant, pleasant aroma, lightweight
Cons: Soft, expensive, requires sealing for color retention
Redwood (2.4 lbs/BF)
Best for: Outdoor decking, pergolas, planters
Pros: Excellent rot resistance, beautiful color, stable
Cons: Very expensive, limited availability
Common Hardwoods
Oak (3.875 lbs/BF)
Best for: Flooring, furniture, cabinets, millwork
Pros: Very strong, beautiful grain, widely available
Cons: Hard to work, moderate to expensive
Maple (3.75 lbs/BF)
Best for: Flooring, butcher blocks, furniture
Pros: Extremely hard, smooth grain, light color
Cons: Difficult to stain evenly, can be expensive
Walnut (4.0 lbs/BF)
Best for: Fine furniture, gunstocks, musical instruments
Pros: Stunning dark color, works beautifully, stable
Cons: Expensive, can be brittle
Cherry (3.0 lbs/BF)
Best for: Fine cabinetry, furniture, decorative trim
Pros: Beautiful color that darkens with age, easy to work
Cons: Expensive, can have gum pockets